diff options
author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-01-17 14:36:51 -0800 |
---|---|---|
committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-02-21 09:03:50 -0800 |
commit | 9b9ec9b90ef481e182927989963274dc2697f9a6 (patch) | |
tree | 977b0fc115b279c25de3200a6bd4d67f1eff83c8 | |
parent | a858af2875fb291d0f4b0a4419fefbf03c2379c0 (diff) | |
download | linux-stable-9b9ec9b90ef481e182927989963274dc2697f9a6.tar.gz linux-stable-9b9ec9b90ef481e182927989963274dc2697f9a6.tar.bz2 linux-stable-9b9ec9b90ef481e182927989963274dc2697f9a6.zip |
rcutorture: Permit holding off CPU-hotplug operations during boot
When rcutorture is started automatically at boot time, it might well
also start CPU-hotplug operations at that time, which might not be
desirable. This commit therefore adds an rcutorture parameter that
allows CPU-hotplug operations to be held off for the specified number
of seconds after the start of boot.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r-- | Documentation/RCU/torture.txt | 13 | ||||
-rw-r--r-- | kernel/rcutorture.c | 12 |
2 files changed, 21 insertions, 4 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt index d67068d0d2b9..01a809b1dbc6 100644 --- a/Documentation/RCU/torture.txt +++ b/Documentation/RCU/torture.txt @@ -69,6 +69,13 @@ onoff_interval CPU-hotplug operations regardless of what value is specified for onoff_interval. +onoff_holdoff The number of seconds to wait until starting CPU-hotplug + operations. This would normally only be used when + rcutorture was built into the kernel and started + automatically at boot time, in which case it is useful + in order to avoid confusing boot-time code with CPUs + coming and going. + shuffle_interval The number of seconds to keep the test threads affinitied to a particular subset of the CPUs, defaults to 3 seconds. @@ -277,5 +284,7 @@ The following script may be used to torture RCU: The output can be manually inspected for the error flag of "!!!". One could of course create a more elaborate script that automatically -checked for such errors. The "rmmod" command forces a "SUCCESS" or -"FAILURE" indication to be printk()ed. +checked for such errors. The "rmmod" command forces a "SUCCESS", +"FAILURE", or "RCU_HOTPLUG" indication to be printk()ed. The first +two are self-explanatory, while the last indicates that while there +were no RCU failures, CPU-hotplug problems were detected. diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index a52b3217c160..2914cafe171b 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -65,6 +65,7 @@ static int fqs_duration; /* Duration of bursts (us), 0 to disable. */ static int fqs_holdoff; /* Hold time within burst (us). */ static int fqs_stutter = 3; /* Wait time between bursts (s). */ static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */ +static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */ static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */ static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */ static int test_boost_interval = 7; /* Interval between boost tests, seconds. */ @@ -95,6 +96,8 @@ module_param(fqs_stutter, int, 0444); MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)"); module_param(onoff_interval, int, 0444); MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable"); +module_param(onoff_holdoff, int, 0444); +MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)"); module_param(shutdown_secs, int, 0444); MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), zero to disable."); module_param(test_boost, int, 0444); @@ -1300,13 +1303,13 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag) "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d " "test_boost=%d/%d test_boost_interval=%d " "test_boost_duration=%d shutdown_secs=%d " - "onoff_interval=%d\n", + "onoff_interval=%d onoff_holdoff=%d\n", torture_type, tag, nrealreaders, nfakewriters, stat_interval, verbose, test_no_idle_hz, shuffle_interval, stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter, test_boost, cur_ops->can_boost, test_boost_interval, test_boost_duration, shutdown_secs, - onoff_interval); + onoff_interval, onoff_holdoff); } static struct notifier_block rcutorture_shutdown_nb = { @@ -1410,6 +1413,11 @@ rcu_torture_onoff(void *arg) for_each_online_cpu(cpu) maxcpu = cpu; WARN_ON(maxcpu < 0); + if (onoff_holdoff > 0) { + VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff"); + schedule_timeout_interruptible(onoff_holdoff * HZ); + VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff"); + } while (!kthread_should_stop()) { cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1); if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) { |